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chaosdsm
Capacitor or fuse replacement

My A/C quit working, It's a 12 year old Lennox system with 2 seperate units. The blower unit is inside the house, while the cooling unit is outside the house. When I went to turn the A/C on last night, I heard a pop, then nothing. The blower wasn't running & the cooling unit wasn't running, so I shut the breakers off for both units. Checked both sub-pannels to both units to see if a breaker had tripped, but they did not. I shut all the breakers off anyway & turned them back on & still no-go, so I shut the main breakers for the A/C off again.

This morning, I took the cover off of the blower to see if I could see anything obvious & to see if there was a fuse somewhere inside the unit that I could check. Although I found a fuse, I cannot figure out how to remove it to check it :confused:

The only thing that stood out to my eyes was the corrosion built up on the capacitor (which is a GE btw): :eek:

Don't worry, I've worked with & around hundreds of capacitors, some considerably larger (& vastly more dangerous) than this little puppy. Anyway, after removing the capacitor & using contact cleaner & a brass bristle brush to clean off the corrosion, & doing the same with the electric connectors on the ends of the wires, it's still not working.

So, if someone is familair with the fuse & specificly, how to remove it so that I can check it, that would be extremely helpful. I'd rather not pay a couple hundred bucks to have an A/C tech come out & replace a $10 fuse or $50 capacitor.

I have one question about the capacitor. I know the replacement needs to be the same specs: 15uf, 370VAC, +/- 6%, 50/60Hz... IIRC, the very bottom number (39H6301) is the series number. I found a NIB GE replacement capacitor with the same specs, but completely different series number, & being 15+ years since I've ordered a replacement capacitor for anything (I've installed several but I didn't order them), I cannot remember if the replacement needs to be of the same or equivelant series??? The only difference that I can readily tell between the two is that the new one has 2 connector tabs per pole instead of one per pole like on the old one.

TIA

djohns
Re: Capacitor or fuse replacement

As far as the Cap. is concerned , as long as the microfarads rating is the same , and the voltage rating is at least 370 volts , that should work . The fuse appears to be on the control power ( 24v ) transformer . If you can't get the fuse out , use a voltmeter to check the transformer output . Does the contactor pull in when the thermostat calls for the unit to run ? If you don't want to call a pro , you'r going to have to have a multi-meter to do some troubleshooting .
And by the way , that cap had better not cost $50 . Probably less than $20 .

Re: Capacitor or fuse replacement

thx for the reply!

It's not the thermostat, I swapped it with a known working thermostat.

As for the price, I just quoted the first one I saw (direct Lennox replacement part btw...), but found a couple others later for $22-$25 with shipping.

If it's not the fuse or cap, we'll call a HVAC service tech. Just don't feel like spending big $$$ if I can fix the problem cheap & easy.

Re: Capacitor or fuse replacement

Turned out to be that transformer with the fuse in it. Swapped it out & we're right as rain :)

djohns
Re: Capacitor or fuse replacement

Glad you came back and let us know . A lot of folks never take the time .

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